The last time Ryan Dempster made a big-game start was October 1, 2008 against the Dodgers in Game 1 of the NLDS at Wrigley Field.

As many of you remember, Dempster didn’t fare too well. He appeared riddled with early-game jitters and his overall performance actually felt worse than his pitching line: 4.2 innings, 4-ER, 4-H, 2-K…7 walks.

James Loney’s fifth-inning grand slam off Dempster erased an early 2-0 Cubs lead and sent Chicago spiraling towards a 7-2 loss–and eventual series sweep at the hands of Los Angeles.

Now four years later, Dempster has his chance at redeeming his big-game poise when starting at Oakland later this afternoon (2:35pm CST). He has not faced the A’s this season.

Meanwhile, having dropped two-straight against the Athletics, Texas is on the brink of wasting what was once a 13-game lead over Oakland. The two clubs enter Game 162 tied atop the AL West division.

Officially, it’s not a playoff game, but it might as well be given the circumstances. And now, more than ever, the Rangers need Dempster to deliver a gem or risk facing a one-game playoff in the wild card round to advance in October.

Dempster’s been as good as advertised since joining the Rangers at the trade deadline (7-3, 4.64), but he’ll have his hands full against a red-hot A’s club that’s won 5-straight and sends AJ Griffin to the mound who’s (7-1, 2.71) over his last 14-starts.

For Cubs fans there’s plenty to root for, and against, depending on how bitter you are from Dempster’s fallout with Chicago after he surprisingly turned down what would have been a lucrative trade with Atlanta this past July.

However, this is exactly what Dempster was holding out for…a chance to play meaningful baseball in October…and a chance to right his playoff misfortunes with the Cubs in 2007-08. Batter up…